flink-filesystems/flink-s3-fs-base/src/main/java/org/apache/flink/fs/s3/common/writer/RecoverableMultiPartUpload.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.fs.s3.common.writer;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.RecoverableFsDataOutputStream;
import org.apache.flink.core.fs.RecoverableWriter;
import org.apache.flink.fs.s3.common.utils.RefCountedFSOutputStream;

import javax.annotation.Nullable;

import java.io.File;
import java.io.IOException;
import java.util.Optional;

/**
 * An uploader for parts of a multipart upload (MPU).
 * The caller can add parts to the MPU and snapshot its state
 * to be recovered after a failure.
 */
@Internal
interface RecoverableMultiPartUpload {

	/**
	 * Creates a snapshot of this MultiPartUpload (MPU) and returns a
	 * {@link RecoverableFsDataOutputStream.Committer Committer} which can be used to finalize the MPU.
	 *
	 * @return The {@link RecoverableFsDataOutputStream.Committer Committer} that can be used to complete the MPU.
	 */
	RecoverableFsDataOutputStream.Committer snapshotAndGetCommitter() throws IOException;

	/**
	 * Creates a snapshot of this MultiPartUpload, from which the upload can be resumed.
	 *
	 * @param incompletePartFile The file containing the in-progress part which has not yet reached the minimum
	 *                           part size in order to be uploaded.
	 *
	 * @return The {@link RecoverableWriter.ResumeRecoverable ResumeRecoverable} which
	 * can be used to resume the upload.
	 */
	RecoverableWriter.ResumeRecoverable snapshotAndGetRecoverable(
			@Nullable final RefCountedFSOutputStream incompletePartFile) throws IOException;

	/**
	 * Adds a part to the uploads without any size limitations.
	 *
	 * @param file The file with the part data.
	 *
	 * @throws IOException If this method throws an exception, the RecoverableS3MultiPartUpload
	 *                     should not be used any more, but recovered instead.
	 */
	void uploadPart(final RefCountedFSOutputStream file) throws IOException;

	/**
	 * In case of an incomplete part which had not reached the minimum part size at the time of
	 * snapshotting, this returns a file containing the in-progress part at which writing can be resumed.
	 */
	Optional<File> getIncompletePart();
}